IL‐15‐induced human DC efficiently prime melanoma‐specific naive CD8+ T cells to differentiate into CTL

P Dubsky, H Saito, M Leogier, C Dantin… - European journal of …, 2007 - Wiley Online Library
P Dubsky, H Saito, M Leogier, C Dantin, JE Connolly, J Banchereau, AK Palucka
European journal of immunology, 2007Wiley Online Library
Monocytes differentiate into dendritic cells (DC) in response to GM‐CSF combined with
other cytokines including IL‐4 and IL‐15. Here, we show that IL15‐DC are efficient in
priming naive CD8+ T cells to differentiate into melanoma antigen‐specific cytotoxic T
lymphocytes (CTL). While both melanoma peptide‐pulsed IL15‐DC and IL4‐DC expand
high‐precursor frequency MART‐1‐specific CD8+ T cells after two stimulations in vitro, IL15‐
DC require much lower peptide concentration for priming. IL15‐DC are more efficient in …
Abstract
Monocytes differentiate into dendritic cells (DC) in response to GM‐CSF combined with other cytokines including IL‐4 and IL‐15. Here, we show that IL15‐DC are efficient in priming naive CD8+ T cells to differentiate into melanoma antigen‐specific cytotoxic T lymphocytes (CTL). While both melanoma peptide‐pulsed IL15‐DC and IL4‐DC expand high‐precursor frequency MART‐1‐specific CD8+ T cells after two stimulations in vitro, IL15‐DC require much lower peptide concentration for priming. IL15‐DC are more efficient in expanding gp100‐specific CD8+ T cells and can expand CD8+ T cells specific for Tyrosinase and MAGE‐3. CTL primed by IL15‐DC are superior in their function as demonstrated by (i) higher IFN‐γ secretion, (ii) higher expression of Granzyme B and Perforin, and (iii) higher killing of allogeneic melanoma cell lines, most particularly the HLA‐A*0201+ Sk‐Mel‐24 melanoma cells that are resistant to killing by CD8+ T cells primed with IL4‐DC. Supernatants of the sonicated cells demonstrate unique expression of IL‐1, IL‐8 and IL‐15. Therefore, membrane‐bound IL‐15 might contribute to enhanced priming by IL15‐DC. Thus, IL‐15 induces myeloid DC that are efficient in priming and maturation of melanoma antigen‐specific CTL.
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